The present invention concerns methods and warp knitting machines for the manufacture of a looped pile warp knit fabric having a pile pattern, the binding warp threads of the fabric ground being fed to a row of needles by a row of warp-thread guides and formed into chain stitches, the chain stitches tying in, between their needles loops and their sinker loops, both the weft (i.e., inlay) threads of the fabric ground and also a system of pile threads.
German Democratic Republic patent application No. WP DO4B/203 314 proposed a method and a crochet galloon machine for the manufacture of a run-resistant looped pile fabric, in which during the formation of every second course, the pile threads are presented to the crochet needles in the same lap as the binding warp threads (i.e., the threads for the chain stitches), with the binding warp threads, however, clamping the pile threads against the shafts of respective needles. When the needles retract, the location at which the respective pile thread is clamped against the shaft of a needle by the respective warp thread shifts, relatively speaking, to the hook of the respective needle. A row of reserve pile loop supports is provided, each such reserve pile loop support being located intermediate two adjoining needles and in front of the conventional pile loop supports of the machine. The reserve pile loop supports extend upwards from below and can be raised to reserve-forming position or lowered to reserve-releasing position. When the reserve pile loop supports are in raised, reserve-forming position, the pile threads presented to the needles are deflected about the reserve pile loop supports, thereby increasing the length of pile thread extending from the pile thread guides to the needles and thus forming a reserve length of pile thread for each needle. When the reserve pile loop supports are then lowered to reserve-releasing position, the reserve length of pile thread associated with each needle is released or freed, the reserve length of pile thread now amounting to an open loop of pile thread. In particular, the respective pile thread associated with each needle stays clamped against the needle as the clamping location shifts to the needle hook during needle retraction, and during further needle retraction and continuing right on to cast-off is able to continue to stay clamped against the needle even during cast-off because the pile thread's reserve length is made available just before cast-off. Accordingly, during cast-off of the old chain stitch of that needle the open pile-thread loop resulting from release of the pile thread's reserve length is pulled through the old chain stitch of the respective needle, i.e., is pulled through to the right side of the fabric.
In that method and machine, the pile thread is clamped against its respective needle in this way only when the binding warp thread (chain-stitch thread) fed to that needle and the pile thread are both presented to the needle as a single lap. However, this occurs in only every second course, the reserve pile loop supports being raised to reserve-forming position, to form a reserve length in each needle's pile thread, only during every second knitting cycle. In that technique, the simultaneous formation of reserve lengths in the pile threads of all needles is performed in order to achieve a uniform consumption of pile threads from off a warp beam from which the pile threads are supplied. Likewise, the reserve lengths of pile thread simultaneously formed at each needle can only be released simultaneously at all needles, in particular by lowering of the mounting bar for the reserve pile loop supports. Using this technique, there does result a run-resistant looped pile fabric, in every second course of which there is contained, in addition to the pile loops formed by ordinary shogging of the mounting bar for the pile-thread guides, pile loops which have been pulled through chain stitches all the way through to the right side of the fabric. To the extent that such an effect can be considered to amount to a pile loop pattern, a pattern exists. However, real and variable patterning capability is not possible with such a technique.